It's between the Wii U and the NES for me.
NES is the one I've personally put the least time into so I've got more fond memories with all the other consoles. However I do recognise it's the birth of Nintendo as we know them and so many great franchises (Super Mario, Zelda etc.) so I've put my vote in for the Wii U. I don't like dissing it as I do think it's underrated but the simple truth is all their other home consoles had greater first party exclusives.